It seems more and more likely that the story is set is an alternate timeline. There were no Sentinels in the original trilogy (apart from in the Danger Room in X3, and an icon on Stryker's computer in X2).

I'm pretty confident that isn't set in an alternate timeline.

The Wolverine had a connection to the original trilogy and DOFP.

Just because there's suddenly a Sentinel program, it doesn't mean its already set in an alternate timeline.